Connector for joining tubular members

ABSTRACT

A connector for releasably joining hollow rectangular tubular members. The connector consists of a cubical body with a plurality of spigots projecting therefrom. Each spigot consists of a rigid core of polygonal cross-section enclosed within a resiliently compressible plastic casing having longitudinal ribs corresponding in number to the number of sides of the tubular member. The diameter of the spigot and casing across the ribs is less than the diameter across the diagonals of the tubular member and greater than the diameter across opposite walls of the tubular member. The locked joint is established by inserting the spigot and casing into the tubular member with the ribs aligned with the corners and, by relative rotation of the tubular member and spigot, opposed ribs are brought into an interference fit with opposed faces of the tubular member with a positive lock resulting.

[4 May 30, 1972 [54] CONNECTOR FOR JOINING TUBULAR MEMBERS FrederickWilliam Reilly, lslington, Ontario, Canada [72] Inventor:

Beautiline Limited, Downsview, Ontario, Canada 221 Filed: Jan. 28, 197121 Appl.No.: 110,397

[73] Assignee:

[30] Foreign Application Priority Data Jan. 20, 1971 Canada ..l03,462

[52] US. Cl. ..287/54 A, 248/239, 287/126 [51] Int. Cl ..E04g 7/00 [58]Field of Search ..248/235, 239, 214, 215, 300-304,

248/307, 340, 287; 287/54 A, 126, 20.92 D, 20.92 Y; 211/148, 153;312/257; 52/283, 495, 498

3,386,590 6/1968 Gretz ..287/54 A 3,532,369 10/1970 Reilly ...287/54 A3,545,625 12/1970 MacMillan ..21 l/l48 FOREIGN PATENTS OR APPLICATIONS656,219 8/1951 Great Britain ..248/235 Primary Examiner-Marion Parsons,J r. Attorney-George l-l. Riches [57] ABSTRACT A connector forreleasably joining hollow rectangular tubular members. The connectorconsists of a cubical body with a plurality of spigots projectingtherefrom. Each spigot consists of a rigid core of polygonalcross-section enclosed within a resiliently compressible plastic casinghaving longitudinal ribs corresponding in number to the number of sidesof the tubular member. The diameter of the spigot and casing across theribs is less than the diameter across the diagonals of the tubularmember and greater than the diameter across opposite walls of thetubular member. The locked joint is established by insetting the spigotand easing into the tubular member with the ribs aligned with the cometsand, by relative rotation of the tubular member and spigot, opposed ribsare brought into an interference fit with opposed faces of the tubularmember with a positive lock resulting.

4 Claims, 10 Drawing Figures PATENTEU MAY 30 I972 SHEET 3 OF 3 lnvenforFrederick W. Reilly I") Le) I 9*? m D Afforney CONNECTOR FOR JOININGTUBULAR MEMBERS This application is an improvement on applicants priorU.S. Pat. No. 3,532,369 dated Oct. 6, 1970.

One type of joint in which a vinyl insert is used has been disclosed inliterature published by Apton, a division of Metalworks Limited.Essentially, the construction consists of a tapered vinyl insert whichis inserted into a tube end. The connector consists of a plurality oftapered spigots, each of size to fit into the vinyl insert. Theconnection is made by hammering each spigot into the respective taperedinsert.

Canadian Pat. No. 841,26l dated May 12, 1970, David H. Peacock inventor,comprises a three part system namely, a square tube, an insert whichfits into the tube and which has thickened portions which bridge thecorners of the tube and a square spigot which fits into the sleeve andlocked therein by rotating the spigot so that the spigot comers jamagainst the thickened corners.

Applicant's U.S. Pat. No. 3,532,369 discloses a joint in which hollowtubular members are joined together by a connector having a plurality ofspigots, each spigot having four diametrically opposite vinyl inserts.The vinyl inserts are separately made and individually affixed inlongitudinal grooves formed on the spigot. To complete the joint, thespigot, with the inserts attached, are aligned with the tube corners andthen inserted; the tube is then rotated about 45 to the locked position.While this makes a satisfactory joint, it is very time consuming whenassembling and also costly to manufacture.

The connector of the present invention for connecting tubular membersinto a unitary frame comprises a spigot consisting of a substantiallyrigid core and a resiliently compressible casing surrounding the coreand secured thereto so that there is no relative rotation between thecore and the casing, the easing having longitudinally extending ribscorresponding in number to inner faces of the tubular member, each ribpreferably having two longitudinally extending cheeks formed by achannel formed centrally in and extending longitudinally of the casing.The diameter of the spigot and easing taken across diametricallyopposite ribs is less than the distance between diagonally oppositecorners of the tubular member and greater than the distance betweenopposite walls of the tubular member by an amount sufficient to producea press fit between the inner walls of the tubular member and said ribswith substantial deformation of the said walls, whereby when the spigotand casing are entered in a respective tubular member and rotated tobring diametrically opposite ribs into engagement with opposed innerwalls, the connector and tubular member are releasably locked together.

The connector of the present invention will now be described withreference to the accompanying drawings which illustrate a preferredembodiment of the invention. It is to be understood, however, that thisis being done by way of illustration and not as a limitation. It will beapparent that alternative constructions can be devised without departingfrom the essential features of the invention.

In the accompany drawings FIG. 1 is an exploded view of a jointconstructed in accordance with this invention with two tubular membersshown connected to the connector and another member being connectedthereto;

FIG. 2 is a cross-section through an assembled joint showing a spigotentered in the tubular insert in its first position;

FIG. 3 is a cross-section on the same line as FIG. 2 with the spigot andtubular member rotated relative to each other through about 45 into alocked position;

FIG. 4 shows an alternative construction, in cross-section, of thespigot and casing;

FIGS. 5, 6 and 7 illustrate cladding clips;

FIG. 8 is a fragmentary perspective view illustrating an additionalfeature for supporting shelves and cladding;

FIG. 9 is a plan view of the assembled comer shown in FIG. 8;

FIG. 10 is a, cross-section on the line 10-l0 of FIG. 9.

The embodiment illustrated in FIGS. 1, 2 and 3 illustrate the inventionin its simplest and preferred form. In this embodiment, the connectorcomprises a cube shaped member 10 having a plurality of spigots -1 1,each of which is enclosed within a resilient compressible casing 12. InFIG. 1, the connector is shown with three tubular members 13, 14, 15which are made of steel or aluminum and are substantially rigid. It isto be noted that the invention is not limited to tubular members ofsquare cross-section.

Each spigot 1 1 projects from a face of the member I0 and at rightangles thereto. Preferably, spigot 11 and member 10 are integrallyformed of rigid material such as metal or hard, rigid plastic. Thespigots are generally square in cross-section, smaller in cross-sectionthan the tubular members and preferably with the comers stepped asindicated at 16 to ensure non-rotatability of the casing hereinaftermentioned.

The resilient compressible casing 12 hereinafter described is made ofplastic, preferably vinyl and is chosen for durability, elasticity,memory and hardness. The casing is made to have an internal bore intowhich the spigot is fitted by a press fit against relative rotation asherein described. In the illustrated embodiment, the exterior of thecasing is generally circular and substantially smaller in diameter thanthe distance between diagonally opposite comers of the tubular memberinto which the spigot is to be fitted. As the connector, in the presentillustration, is to be used in connecting tubes having a substantiallysquare cross-section the casing 12 is formed with four diametricallyopposite ribs 17,18,19,20 thus corresponding in number to the number ofthe walls of the tubular member. The combined diameter across the spigotcasing and ribs is greater than the distance between opposite walls ofthe tubular member. In actual practice, it has been found thatsatisfactory locking as hereinafter described, can be obtained by havingthe casing diameter, across the ribs, greater by approximately 0.005inch than the distance between diametrically opposite walls which willprovide an adequate press fit without undue bulging of the tube walls.

Each rib extends longitudinally on the casing and has a longitudinalchannel 21 formed centrally thereof to divide each rib into a pair ofcompressible cheeks 23,24 in side-by-side relationship. 1

FIG. 4 illustrates an alternative construction in which the spigot 11,in cross-section, in the form of a Greek cross, having four limbs ofequal length, and the casing 12 is similarly formed to fit over thecore. In this construction, the casing is formed with four resilientlycompressible pads 60,61,62 and 63 which cover the ends of the four limbsas shown. Each pad is divided into a pair of cheeks 23a, 24acorresponding to the cheeks 23,24 in FIGS. 1 to 3. The pads 60,61,62 and63 correspond to ribs 17,18,19,20 in FIGS. 1 to 3.

In proceeding to assemble tubular members, the first step is to insertthe spigot with its casing into its respective tubular member, e.g. thetubular member 13, with the cheeks aligned with the comers of thetubular member 13 as shown in FIG. 2. The tubular member and the spigotare then rotated about 45 relative to each other which will bring theminto the position shown in FIG. 3. The cheeks are then compressed sothat there are flat surfaces which engage against the flat walls of thetubular member and thus provide a positive positioning and releasablylocking of the connector in its correct assembled position. Theresilience of the walls of the member 13 also cooperate in the locking.Since vinyl acts like rubber, it is evident and it was established bytests carried out, that the vinyl flowed to form flat surfaces againstthe tube flat surfaces. Surprisingly too, locking is easier thanunlocking'which is a clear gain in constructional work. Tests showedthat once the cheeks have settled into place considerably more effort isneeded in rotating the connector from the locked position (FIG. 3) tothe unlocked position (FIG. 2).

Referring now to FIGS. 5 to 9, there is illustrated, a device for usewith the spigot by means of which cladding and shelving may besupported.

FIG. 5 illustrates one form of the device which comprises a pair of legs31,32 joined together at the top by a cross-bar 33. Projecting outwardlyfrom the leg 32, is a shelf supporting projection 34. The distancebetween the top edge of the projection 34 and the top edge of the bar 33is equal to the thickness of the shelf which is to be supported thereby.This is used as the top clip for supporting a table top having shelvesand vertical walls or cladding as will be clearly seen in FIG. whichwill be described in detail later.

Referring now to FIG. 6, the clip is of particular usefulness as thesupport for the bottom shelf and also the cladding; the clip comprisesspaced apart legs 36,36 with a cross member 37 spaced intermediate theends to provide recesses which receive the edges of the cladding andalso to straddle the spigot as shown in FIG. 9 and which will bedescribed later. The bottom portion of the leg 36 is provided with ashelf supporting projection 38.

Referring now to FIG. 7, the clip shown is for use in intermediateshelving and also for securing the cladding in place. The clip comprisesspaced apart legs 39,40 joined together by a cross-bar 41 which isspaced relative to the ends of the legs so that a slot will be formedfor the edges of the cladding and also to span the core 11 of theconnector. A shelf supporting projection 40a is also provided.

FIGS. 8, 9 and 10 show the cladding clip in use in association with askeletal frame formed of tubular members connected together by theconnector of the present invention. The skeletal frame is fragmentarilyillustrated and consists of a pair of horizontal tubular frame members42,43 and upright tubular frame members 44,45 joined together, for thepurpose of illustration only, by the connector hereinbefore described.The clips are set in position on the spigots so that the tube end can bejammed tightly against the clip during the step of connecting the tubeto the connector. In FIG. 8, the connector illustrated in FIG. 5 isshown in relation to the horizontal tubular member 42 and the clip ofFIG. 6 is shown in relation to tubular member 43. This is to illustratethe manner in which the cladding 46 and a shelf 47 are supported.

FIG. 10 illustrates a structure comprising a top shelf 48, bottom shelf49, the intermediate shelf 47, upper cladding 46 and lower cladding 52.In FIG. 10, the upper shelf 48 and the upper edge of the cladding 46 aresupported and retained in position by a clip similar to the one shownand described in FIG. 5. The intermediate shelf 47, the bottom edge ofthe cladding 46 and the upper edge of the cladding 52 are supported andretained in position by a clip similar to theone illustrated anddescribed with reference to FIG. 7. The bottom shelf 49 and the bottomedge of the cladding 52 are supported by and retained in position by aclip similar to that shown in FIG. 6.

What I claim is:

l. A connector for connecting tubular members having an internal squarecross-section comprising in combination:

a. a solid body having a plurality of spigots, adapted to be inserted inthe tubular members, each spigot projecting outwardly from a differentface of said body, the number of spigots corresponding to the number oftubular members to be joined together by one connector,

b. a one piece resilient compressible casing completelycircumferentially enclosing each spigot and secured thereto to rotatetherewith, said casing having longitudinally extending, diametricallyopposite compressible ribs corresponding in number to the number ofinternal flat walls of the tubular member,

the diameter taken across diametrically opposite ribs being less thanthe length of the diagonals across the comers of the tube and greaterthan the distance between diametrically opposite walls of the tubularmembers by an amount to provide a press fit between the ribs and theinner walls of the tubular member whereby when a spigot with itscompressible casing is entered in its respective tubular member androtated to bring each rib into engagement with its respective wall, thespigot and the tubular member are releasably locked together.

2. A connector according to claim 1 in which each rib is divided into apair of side-by-side longitudinally extending flat surfaced cheeksforming a stop locating the spigot in its fully locked position.

3. A connector according to claim 1 in which each spigot is formed as asolid square with steps in each longitudinal corner in which an opposingportion of the casing engages.

4. A connector according to claim I in which the spigot has across-section in the shape of a Greek cross having four armssubstantially shorter than the distance between opposing faces of thetubular member and the envelope is of tubular shape and the said ribsare constituted by four thickened portions to form said compressibleribs along the entire length of the envelope and of a thickness slightlygreater than the distance between free ends of the arms and thecontiguous and the opposing face of the tubular member, and uniformlycircumferentially spaced at intervals, each of said thickened portionshaving a recess on the inner wall, said recess receiving the free end ofa cross arm to thereby restrain relative rotating movement between theenvelope and the spigot.

1. A connector for connecting tubular members having an internal squarecross-section comprising in combination: a. a solid body having aplurality of spigots, adapted to be inserted in the tubular members,each spigot projecting outwardly from a different face of said body, thenumber of spigots corresponding to the number of tubular members to bejoined together by one connector, b. a one piece resilient compressiblecasing completely circumferentially enclosing each spigot and securedthereto to rotate therewith, said casing having longitudinallyextending, diametrically opposite compressible ribs corresponding innumber to the number of internal flat walls of the tubular member, thediameter taken across diametrically opposite ribs being less than thelength of the diagonals across the corners of the tube and greater thanthe distance between diametrically opposite walls of the tubular membersby an amount to provide a press fit between the ribs and the inner wallsof the tubular member whereby when a spigot with its compressible casingis entered in its respective tubular member and rotated to bring eachrib into engagement with its respective wall, the spigot and the tubularmember are releasably locked together.
 2. A connector according to claim1 in which each rib is divided into a pair of side-by-sidelongitudinally extending flat surfaced cheeks forming a stop locatingthe spigot in its fully locked position.
 3. A connector according toclaim 1 in which each spigot is formed as a solid square with steps ineach longitudinal corner in which an opposing portion of the casingengages.
 4. A connector according to claim 1 in which the spigot has across-section in the shape of a Greek cross having four armssubstantially shorter than the distance between opposing faces of thetubular member and the envelope is of tubular shape and the said ribsare constituted by four thickened portions to form said compressibleribs along the entire length of the envelope and of a thickness slightlygreater than the distance between free ends of the arms and thecontiguous and the opposing face of the tubular member, and uniformlycircumferentially spaced at 90* intervals, each of said thickenedportions having a recess on the inner wall, said recess receiving thefree end of a cross arm to thereby restrain relative rotating movementbetween the envelope and the spigot.